This invention is related to micrometers and more specifically to electronic micrometers.
The conventional precision micrometer typically comprises a spindle attached to a cylindrical thimble and threadedly mounted in a cylindrical hub. When taking a measurement with the micrometer, the thimble and the spindle are turned relative to the hub and the amount of travel is used as an indication of the measured distance. To read the measurement taken, three readings must be taken. For the first reading, the position of the forward edge of the thimble upon the scale which runs along the hub must be determined. Reference is then made to the thimble calibration lines to determine which one is nearest to a line on the scale on the hub. In most cases, the reading will fall between two calibration lines on the thimble scale. Its exact position between two such calibrations is determined by a third reading, made by determining which of the five lines on the hub is most nearly opposite the calibration line on the thimble scale.
As can easily be seen, more than a glance at the micrometer is required to determine the measurement taken. In industrial use, where lost time can be quite significant, it would be desirable to be able to take micrometer readings instantaneously. In addition, a digital readout indicating the measurement would be highly desirable since the problem of inaccurate determination of the measurement could be minimized.